(1) Field of the Invention
This invention relates to a rotary type injection apparatus used for molding synthetic resins in which a plurality of molds are mounted on a turntable, clamping is performed together with the turntable to effect injection molding, and removing of molded articles is performed by transferring molds to other positions together with the turntable.
(2) Prior Art
A rotary injection molding machine is already known in which a turntable is provided on the upper surface of a machine bed or internally of a fixed table mounted on the machine bed, one of plural sets of split molds are mounted at predetermined intervals whereas the other of split molds are mounted on a clamping table of a clamping device provided opposedly of the turntable, and injection molding and article-releasing are carried out at various positions every stop of the turntable.
Since one of the split molds are mounted on a turntable, pouring of resins into the molds in the aforesaid rotary type injection molding machine is carried out from the side of the molds, in other words, from the direction at a right angle with respect to the clamping direction. Particularly, in the mold provided with a plurality of cavities, a runner passage has to be provided to distribute the resins to these cavities. A runner plate and a mold have to be placed one above the other and set to the turntable in order to form the runner passage. In setting this, consideration has to be made so that in the releasing position, both the molded article and runner may be removed. This poses various problems such that the construction of molds becomes complicated to increase the cost, setting of the runner plate and releasing means for each mold increases the weight of molds, and in addition, the large mass of the turntable requires a great force for rotating and stopping same.
Further, in the rotary type injection molding machine, a cavity gate is provided on a cavity mold to facilitate releasing of the runner, and for a so-called inner gate whereby the resin is poured from the inside of the molded article, a special construction of a mold has to be employed.